US2074163A - Railway signaling system - Google Patents

Description

Mmh A16, 1937. G. CAME y 2,074,163

RAILWAY SIGNALING SYSTEM Filed March 28, 19:54 s sheets-'sheet 1 C f/g/ *f e7 V 2\ L K Illa/m m *s e B A X F"i 2x 'o lg.' C5 5l 52 53 R www EDR; s Uil 3 .X lz ..1 x X Bl /5 FR, B i -:Ifj B* H23 f f klo' /5 Mo l //1 8X X J [4J-J6 B l [M55/ix 2LP/4 if C Figs.

Ck X 2o l8- FR I 23 TR A /9 'l um 'lg/r I 16, 1937. Q CAILLE 2,074,163

RAILWAY SIGNALING SYSTEM Filed March 28, 1954 3 Sheets-Sheet 2 INVE/Vml? Geo/gaf Caille B22/RM Hi.;q ATTORNEY ch E6, E37 G. CAILLE ZWMB i RAILWAY SIGNALING SYSTEM Filed March 28, 1954 s sheets-shea s INI/N701? Gpofgew Cai Il@ BY His ATTog/vEr/ Patented Mar. 16, 1937 Nunirse RAliLWAY SIGNALING SYSTEM of Pennsylvania Application March 28,

1934, Serial No. V'717,821

In France April l2, 1933 15 Claims.

This `invention relates, to railway signaling systems of the kind in which track circuits constituted bythe track rails divided into block sections are utilized for the automatic control of the signals of the system in accordance with the presence or absence of a train or vehicle in or from a block section.

In signaling systems of the character above indicated the track circuits are usually arranged to be continuously supplied with signaling cur- -rent with a correspondingly continuous expenditure of electrical energy and the invention has for its vprincipal object to provide a signaling system of lthe track circuit type in which signaling current is arranged to be supplied to the track circuit of a .block section only upon the approach of a train or vehicle, the track circuit -being deenergized except under these conditions.

In existing signaling systems comprising continuously energized track circuits the presence of a train or vehicle in a block section is arranged to be detected for the purpose of controlling signal indications by means of a track relay connected across the track rails of the section so as to be deenergized by the wheels and axles of a train or vehicle entering the section, but it will be evident that this arrangement cannot be Vadopted'in a signaling system in which the track circuits are not continuously energized since the track relay Will be deenergized under normal conditions Whether the section is or is 'not occupied by a train or Vehicle.

A further object of the invention is accordingly to provide arrangements for detecting the `:lnesence of a train or vehicle in a block section underall conditions of operation whenever such detection is required, a still further object of the invention being to provide a signaling system comprising track circuits which are not continuously energized, in which the failure of the supply of electric current to any portion of the system will cause a danger signal to be given and'thus ensure complete safety in operation.

The invention is illustrated by way of example in the accompanying drawings of which Figure 1 is a diagrammatic View of the circuit connections of a portion of a track circuit signaling system illustrating the principle of the invention.

Figure 2 is a diagrammatic View ci a number of successive block sections of a railway track provided with a signaling system embodying one form of the invention.

Fig. 2EL is a diagrammatic view, similar to Fig. l, showing the control circuit for the disagree- .0.55 ment relays of Fig. 2-

Figure 3 is a diagrammatic view similar to `a portion4 of Figure l 'illustrating certain c1rcu1t connections,

tion.

Figures 5 and 6 are diagrammatic views illustrating two dilferent embodiments of the invention as applied to the control of the signals for a number of successive block sections of-aV railway track. 1 i

Referring now first to Figure 1, it will be seen that the track rails of a block section 'C are indicated at l, 2 as isolated from the track rails of the preceding and succeeding block sections by the usual insulated joints 3. The block section C is provided with a track relay TR connected across the track rails l, 2 in the usual manner and is also provided with a track feed relay FR adapted to be controlled in any suitable manner by the approach of a train or vehicle towards the block section C.

The feed relay FR is provided with relay contacts adapted to control the supply of signaling current to the track rails l, 2 in such a mannerl that this supply is effected when a train or vehicle approaches the block section, the feed relay being thereby caused to occupy what may be termed its feed position, while under all other conditions the feed relay is caused to occupy its non-feed position.

The track relay TR is in its energized position when signaling current is supplied to the track rails I, 2 and the block section is unoccupied by a train or vehicle, this relay'assuming its deenergized position when the block section is occupied or when signaling current is not being supplied to the track rails.

As already explained the presence of a train or vehicle in the block section cannot under all conditions be detected by the deenergization of the relay TR and in accordance with the principle of the invention the positions of the feed and track relays FR and TR relative to each other as distinct from the actual positions of either of these relays is arranged to indicate whether the block section is occupied or unoccupied.

When the track relay TR is in its energized position and the feed relay FR is in its feed position, the two relays may be said to be in agreement with each other as is the case also when the track relay TR is in its deenergized position and the feed relay FR is in its non-feed position.

When, however, the track relay TR is in its deenergized position with the feed relay FR in its`A Figure 4 being a similar view of a modicau feed position or if the track relay TR should be in its energized position with the feed relay FR in its non-feed position the two relays may be Said to be in disagreement with each other.

The feed position of the feed relay FR may be arranged to correspond either to the energized (Fig. 2a arrangement) or deenergized (Fig. 1 arrangement) of this relay and it will be evident that the relays TR and FR in either Fig. 2a or Fig. 1 will be in agreement with each other only when a train or vehicle approaches the block section and this section is unoccupied.

In the simple system illustrated diagrammatically in Figure 1 the relay FR is arranged to assume its feed position when deenergized, this relay being normally energized and being deenergized by means not shown when a train or vehicle approaches the block section C in the direction indicated by the arrow. The system of Fig. 1 saves power in that the track circuits are normally deenergized, but some power is, of course, expended in maintaining the feed relays FR normally energized.

` 'I'he signal S at the entrance to the block section is shown as arranged to be controlled by an electrically operated device DR of any suitable type and it will be seen that under normal conditions the relay FR being energized and in its non-feed position, so that the relay TR is deenergized, a circuit is completed from a terminal B of a source of electric current through the device DR, back contact 4 of relay TR, wire 5, front contact 6 of relay FR to the other terminal X of the source of current.

The device DR is thus energized and operates the signal S to give a proceed indication.

In the event of failure of current supply to the relay FR the circuit for the device DR will be broken at the contact E so that the device DR will be deenergized and will operate the signal S to give a stop indication.

A similar action will evidently take place in the event of failure of the current supply to the ldevice DR or in the event of current from an extraneous source being supplied to the track rails I, 2 so as to energize the relay TR and interrupt the circuit of the device DR at the contact 4.

When a train or vehicle approaches the block section the relay FR is deenergized and assumes its feed position in which current is supplied to the track rails I, 2 from terminal B, back Contact 'I of relay FR, wire 8, rails I and 2, wire 9, back contact I of relay FR to terminal X.

Assuming that the block section C is unoccupied the relay TR will become energized and a circuit will be completed from terminal B, device DR, front contact 4 of relay TR, wire I I, back contact 6 of relay FR to terminal X.

The device DR under these conditions will still be energized so as to cause the signal S to give a proceed indication.

Under these conditions it will be seen that the proceed signal indication is due to the relays TR and FR being in agreement with each other.

If, however, the block section C is occupied when the train approaches, the relay TR will be deenergized although the relay FR is in its feed position, so that the relays TR and FR will be in disagreement with each other and the circuit of the device DR will be broken at the front contact 4 of the relay TR thereby causing a stop signal indication to be given at the signal S.

Assuming that the block section C is unoccupied and the train consequently enters the block section, the relay FR is arranged to remain .deenergized and the relay TR being deenergized by the presence of the train, the relays TR and FR will consequently be in disagreement with each other so that a stop signal indication will continue to be given at the signal S so long as the train remains in the block section. The deenergization of relay FR during occupancy of section C will be clear from the description of Fig. 5, in which a similar operation takes place.

When the train passes out of the block section the relay FR is reenergized and assumes its nonfeed position so that the relay TR is deenergized and the two relays being thus again in agreement with each other, a proceed signal indication is given at the signal S.

Referring now to Figure 2, three successive block sections CI, C2, C3 of a section of railway track are shown therein and are provided with corresponding signals SI, S2, S3. The feed relays FRI, FR2, FR3 for the sections CI, C2, C3 respectively are in this case arranged to assume their feed positions when energized. Each block section is provided with detector relays DRI, DR2, DR3 which are arranged to be controlled so that each detector relay is energized when the corresponding track and feed relays of the section are in agreement with each other, that is, are either both energized or both deenergized, as indicated by the circuits for relay DR in Fig. 2l,

(the detector relay being deenergized when the track and feed relays are in disagreement.) Referring for the moment to Fig. 2a, it will be seen that the circuit of this figure differs from the circuit of Fig. 1 in that not only the track relays TR, but also the feed relays FR are normally deenergized, thus effecting a maximum saving in power. In contrast to the manner in which relay DR of Fig. 1 is controlled, the energization of relay DR in Fig. 2a requires that relays TR and FR be both energized, or both deenergized, in order that the condition of agreement be established.

Referring again to Fig. 2, the track relays 'I'R for the track sections of this figure are not shown, for simplicity, but it will be understood that the control circuits for the relays DR in Fig. 2 are arranged as shown in Fig. 2a. Each of the feed relays is arranged to control the supply of signaling current to the track rails of the corresponding block section through relay contacts 'I, I8 as shown in the case of the block section C2 and each block section is provided with a track relay (not shown) connected across the track rails in the usual manner as shown in Figure 2a.

Assuming that the block sections C2 and C3 are unoccupied and that a train is present in the lock section CI, the detector relay DRI will be deenergized since the track and feed relays of the section CI are in disagreement, the feed relay FRE being energized through a circuit from terminal B, back contact I2 of relay DRI, wire I3, relay FRI to terminal X. 'I'he relay DRI also completes through a back contact I4 a circuit causing a stop signal indication to be given at the signal SI.

A circuit is also completed under these conditions from terminal B through back contact I5 of relay DRI, wires I6, I1, relay FR2 to terminal X, so that the relay FR2 is in its feed position and effects the supply of signaling current to the track rails of block section C2. Since this block section is unoccupied the detector relay DR2 is energized owing to the track and feed relays of this section being in agreement and a circuit is completed at the front contact I4 of relay DR2 ."to cause the signal S2 to give a-proceed indication.,

The track and feed relays of block section C3 `being also in agreement the detector Vrelay DR3is energized `and a proceed signal is thus also given at the signal S3.

In theevent of the section C2 being already occupied it will be understood that the `track and "feed relays of this section will be in disagreement so that the detector relay DR2 will be deenergized xand a circuit will be completed at'the back contact I4 of this relay to cause the signal S2 to give a stop indication.

Assuming, however, that the section C2 is unoccupied and that the train proceeds to pass'out `of section CI and to enter section C2, the detector relay DRI will become energized as soon as the train has left section CI and will thus interrupt the circuit of relay FRI .at the contact I2 and the circuit of relay FR2 at the contact I5.

While the train is passing from section CI `tosection C2, however, the detector relay DR2 will become deenergized Vowing tothe deenergization of the track relay of this section and the relay `FRZiwill continue to be energized through a `circuit fromterminal'B, back contact I2 of relay `FR2, wire Il, relay DRZ to the terminal X.

The deenergization of the relay DR2 will cornplete at the back contact I4 of this relay a circuit causing the signal S2 to give a stop indication and at the back contact I5 of relay DR2 a circuit lelfecting the energization of the feed relayFR3 of the section C3.

It will thus be seen that as the train proceeds the feed relay of each block section is energized `asthe train enters the preceding block section `and is maintained energized until the train has `completely passed outof the block section.

` `At a terminus the feed relay of the rst block section is arranged to'be'caused to assume its feed position by the train Vpassing over a pedal switch -iorV by any other suitable device.

Referring now to Figure 3, the arrangement just described is utilized in the case of each block section, a normally closed pedal switch P being 4provided at a suitable position in advance of the l entrance to the block section C.

The feed relay FR for the section is normally energized through a holding circuit from terminal B through switch P, wire I8, front contact I9 of relay FR, wire and relay FR to terminal X. The relay FR as. in the system of Figure 1 is, when energized, in its non-feed position so that signaling current is not supplied to the track rails of the section C.

The track relay TR is thus deenergized but as the train passes over the pedal switch P, the circuit of the feed relay FR is broken and the relay FR assumes its deenergized and feed position.

`gIn the event of the block section C being unoccupied the track relay'TRis thereupon energized and the track and feed relays of this section being in agreement, the signal S is caused to give a proceed indication. r

As the train passes off the pedal switch P, this switch is reclosed but the entrance of the train into the block section C causes the deenergization of the relay FR to continue owing to its circuit being broken at the relay contact 2l, the original energizing or holding circuit of the relay FR having been broken at the relay contact I9 when the relay was first deenergized by the action of the pedal switch P.

The feed relay FR thus continues to be deenergized and to occupyits feed position until the train has passed completely through and out o1 the block section C whereupon the track relay TR `is reenergized and closes its contact 2| so that the relayY FR is energized over a pick-up circuit through wires I8 and 22, front contact 2|, andr wires 23 and 2U. The movement of the relay FR kto its energized and non-feed position causes the `relay TR to be deenergized and to open its contact 2| `but the relay FR is maintained energized `through its holding or stick contact I9.

The system of Figure 4` is similar to that of Figure 3 except that the pedal switch P of Figure 3 is replaced by the Contact 24 of a relay PRZ which is connected across the track rails of the block section CI in advanceof the section C2. It will be understood that when a train is present in this section CI the relay PR2 is deenergized and interrupts the energizing circuit of the relay FR2 at the contact 24 of relay PR2. In other respects `the operation of the system of Figure 4 is the same as that of Figure 3 above described.

Referring now to Figure 5 it will be seen that a number of successive block sections CI, C2, C3, C4 are indicated as adapted to be supplied with signaling -current from alternating current supply conductors 25 extending along the track, track transformers TI, T2 etc. being provided for each block section, the secondary windings of these transformers being connected to the track rails I, 2 as shown. Each block section is also provided with its respective alternating current track relay TR2, TR3 etc., each of these relays being of the two element type comprising a track Winding 23 connected across the track rails I, 2

and a local winding 21 supplied at times with current from the lsupply conductors 25. The block sections are also provided with their re- Spective feed relays FR2, FR3 etc., repeater feed relays RFRI, RFR2 etc., forthe corresponding feed relays FR2, FR3 etc.; detector relays DR2, DRS etc., repeater detector relays RDR3, RDR4 etc., for the detector relays DR3, DRfl etc.; and signal control relays SR2, SR3 etc.

Each block section is'also provided with its respective signal SI, S2 etc., at the entrance end of each section and the various relays above referred to with the exception of the track relays TR2, TR3 etc.,` are arranged to be supplied with unidirectional current from rectiiiers WI, YW2 etc., connected through transformers TWI, TWZ etc., to the supply conductors 25, the operation of the system being as follows:

Under normal conditions assuming that the block sections CI, C2, C3, C4 are all unoccupied the feed relays of the block sections are main- E,

tained energized, the circuit of the feed relay FR4 for instance being completed from the positive output terminal of rectifier WI, wires 28 and 29, front contact 30 of relay DB2, wire 3|, front contact 32 of relay DRS, wire 33, front contact 34 of relay FR4, wire 35, relay FRA and wires 33 and 3l to the negative output terminal of rectifier W3 which is connected to the corresponding negative terminals of the'other rectifiers W2, WI

of the system by a common wire 38. It will thus Each of the feed relays FR2, FR3 etc., being in its energized position, the corresponding repeater feed relay RFR2, RFR3 is also in its energized or non-feed position, the circuit of the repeater feed relay RFR2 for instance being completed from the positive terminal of rectier WI, wire 28, front contact 40 of relay FR2, wire 4I, relay RFR2, wire 42 and common wire 38 to the negative terminal of rectier WI. The repeater relays RFRI, RFR2 etc., being thus energized the circuit of the wires 43 leading from the supply conductors 25 to the primary windings of the transformers TI, T2 etc., is broken at the contacts 53 of the relays RFRI, RFR2 etc.

The feed relays FRI, FR2 etc.,beingin their energized or non-feed position and the corresponding track relays TRI, TR2 etc., being deenergized, the feed and track relays of each block section are in agreement with each other as illustrated by the agreement circuit of Fig. l so that the corresponding detector relays DR2, DR3 etc., are energized. In the case of block section C2 for instance it will be seen that a circuit is completed from the positive terminal of rectifier WI, wire 28, front contact 46 of feed relay FR2, wire 44, back contact 45 of track relay TR2, wire 46, detector relay DR2 and wires 4l and 48 to the negative terminal of rectifier WI.

The detector relay of each block section being energized the corresponding repeater detector relay is also energized, a circuit being completed in the case of the repeater detector relay RDR4 for instance from the positive terminal of rectier W3, wires 49 and 5B, front contact 5I of detector relay DRI-l, wire 52, relay RDR4, common wire 38 to the negative terminal of rectier W3.

Each of the signal control relays SR2, SRS is also energized, the circuit for the relay SR3 for instance being completed from the positive terminal of rectifier WI, through wires 23 and 29, front contact 3i) of relay DR2, wire 3l, relay SH3, wires 42 and 38 to the negative terminal of the rectifier WI.

Each of the signals SI, S2 etc. is arranged to be jointly controlled by the signal control relay, and the track and repeater detector relays in such a manner that under normal conditions with the signal control relays energized operating current is not supplied to the signals SI, S2 etc. When, however, a train or vehicle enters a block section, for instance the section C2, the consequent deenergization of the signal control relay SRS causes operating current to be supplied to the signal S3 to cause this signal to give a stop, caution or proceed indication. The signal control relays SRI, SR2 etc., thus serve as approach signal relays and prevent any signal indication from being given until actually required by a train approaching a block section.

The particular signal indication given under these conditions is dependent upon the traffic conditions in a block section and in the block section ahead. In the case of a train entering the block section CI for instance the feed relays FR2 and FR3 will both be operated to their feed positions as will be hereinafter described. If now another train or vehicle is occupying the block section C2 the track relay TR2 will be deenergized by the presence of the train or vehicle and the relay TR2 is arranged when deenergized to control a signal operating circuit for a stop indication at the signal S2.

Ii, however, the block section C2 is unoccupied but another train or vehicle is present in block section C3, the track relay TR2 will be energized but thedetector relay DRS will be deenergized owing to the relays TR3 and FR3 being in disagreement with each other. The repeater detector relay RDR3 will also be deenergized and the energized track relay TR2 and the deenergized yrepeater relay RDR3 jointly control a signal operating circuit for a caution indication at the signal S2.

In the event of both the block sections C2 vand C3 being unoccupied the track relay TR2 and the repeater relay RDR3 will be energized and under these conditions these relays will control an operating circuit for a proceed indication at the signal S2. v

Referring now to the supply of signaling current to the track rails I, 2 of the block sections in advance as a train or vehicle passes along the track, let it be assumed that the train or vehicle is occupying section CI and proceeding towards section C2.

The feed relay FR2 of section C2 has been deenergized by the action of the train entering the section immediately'in advance of the block section CI (which entry caused the associated DR relay to release) so that the energizing circuit for the repeater feed relay RFR2 is broken' at the relay Contact 4I) of relay FR2. A circuit for the track rails of block section C2 from the supply wires 25 to the primary winding of the transformer T2 is thus completed at the back contact 53 of relay RFR2.

At the moment when relay FR2 became released and before relay TR2 closed its front contact 45, relay DR2 was momentarily without energy. Due to the slow releasing characteristic of relay DR2, however, this relay remains in its picked up position until an agreement circuit is again established over back contact 4I! of relay FR2 and front contact 45 of relay TR2. During the time that rthetrain remains in section CI, relay TR2 remains picked up since both of its windings 26 and 21 remain energized. Consequently, relay TR2 does not release until the train enters section C2.

The detector relay DRI (not shown) is deenergized because the entry of the train into section CI caused the associated track relay TRI (not shown) to become deenergized, thus establishing a disagreement between relays TRI and FRI (not shown) which disagreement results in the interruption of the circuit for relay DRI in the same manner that a disagreement between relay FR2 and TR2, for example, results in an interruption of the circuit for relay DR2. The release of relay DRI interrupts the circuit of the relay FR3 through wire 55, front contact 56 of energized relay DR2 and wire 51 so that relay FR3 is deenergized. The corresponding repeater relay RFR3 is also deenergized by the interruption of its circuit at front contact 58 of relay FR3. Relay RFR3 closes its back contact 59 and completes a circuit from'the supply wires 25 to the primary winding of the feed transformer T3.

Let it be assumed that with sections C2 and C3 unoccupied, a train enters section CI. Relay FR2 will have been released due to the entry of the train into the section preceding section CI, and relay FR3 will now release because the energizing circuit for this relay will be opened at the front contact of the detector relay (not shown) associated with section CI even though contact 56 of relay DR2 remains closed. The repeater relays RFR2 and RFR3 will also be deenergized as a result of the released condition of relays FR2 and FR3. Track circuit current was applied to section C2 when relay FB2 released, over theback contact 59 of relay RFRZ, and current is now also supplied to section C3 over theV back contact 59 of relay RFR3.

As a result, track relay TR3 becomes energized because its winding 26 is energized from the track and its local circuit is closedat contact 39. Track relay TR2 remains energized, having been picked up in the same manner as relay TRl (not sho-wn) when the train entered the section preceding section Cl. Since there is now a new condition of agreement between the feed relay FR3 and the associated track relay TR3, the detector relay DR3 which was momentarily deenergized during the transfer interval of relays FR3 and TR3 becomes re-energized without releasing its con tacts and maintains the detector repeater relay RDR3 in its picked up condition, thus avoiding a flash of signal S2. Approach relay SR2A .is released because of the released condition of the detector relay (not shown) associated with section Cl. With relay SR2 deenergized and re lays TR2 and RDR3 both energized, an obvious energizing circuit is closed for the proceed or topmost unit of signal S2.

When the train enters section C2, the track relay TR2 releases and closes the energizing circuit for the stop unit of signal S2. The resulting disagreement between relays FR2 and TR2 causes relay DR2V to release, which releases, in turn, relay RDR2 (not shown), thus preparing an energizing circuit for the caution unit of the entering signal for section CI. This caution signal will not be displayed, of course, unless a following train isv approaching section Cl, and not until the train fully clears the section Cl.

The entry of the train into section C2; also causes the release of feed relay FRll, due to the opening of contact 30 of relay DR2. Current is, therefore, supplied to the rails of section C4 so that relay ".[R4 picks up, its local circuit having been closed at back contact 39 of relay FR4. Accordingly, under the above condition, relays TR4, DR4, RDR4, and SR4 are all energized and relay FR4 is released. The same conditions exist in section C3, except that relay SR3 is released, thus energizing the proceed unit of signal S3.

When the train completely clears section C2, track relay TR2 picks up andl since relay FR2 is released, anA agreement circuit is established which causes relay DR2 to pick up. When relay DR2 picks up, it closes the pickup circuit for relay FRZ which picks up, in turn, and remains energized thereafter over its own holding circuit. The pickup of relay FRZ opens the local circuit of relay TR2 at contact 39, releasing the track relay. Also, the closing of front contact 4U of relay, FR2 energizes relay RFRZ which cuts olf theV rail,current for section C2 'at contact 59. During the transfer interval when relay FR2 picks up and before relay TR2 becomes fully released, relay `DR2 is momentarily on open circuit but does-not release because of its slow-acting characteristic. The apparatus for section C2 is now fully restored to the condition illustrated in Fig.,5.

The pickup of relay SR2 overV front contact 56 of zrelayDR2 deenergizes signal S2 behind `the train, unless a following train has entered section CI or is approaching this section. The sequence of operation taking place when the train enters section C3 and the following sections will be clear without added explanation.

Although the control circuits for signal S2 only are illustrated in detail in the drawings, the circults for' the remaining signals willbe obvious since these signals are controlled in a similar manner.

The manner in which the supply of signaling current to the track rails of each block section is cut olf as the train or vehicle proceeds along the track will now be described with reference to a train assumed to be passing through block sec-` tion C3 and entering block section C4.

So long as the train is in block section C3 the feed relay FR3 and the track relay TR3 are deenergized so that the circuit of the detector relay DR3 is broken at the front contact 58 of relay FR3 and relay DR3 accordingly remains deenergized. Relay FR3 was, of course, deenergized when the train entered section Ci and this relay will remain in its deenergized condition until such time as relay DR3 closes a'pickup circuit for relay FR3 at front contact 64. This will not occur, however, until the train fully clears section C3 because it is only then that track relay 'IRB will pick up, establishing a condition of agreement between relays FR3 and TR3 which results in the pickup of relay DR3.

The block sections Cl and C2 being assumed to be unoccupied the detector relay DR2 and the corresponding relay DRI (not shown) of the section Clare both energized.

As soon as the train has passed out of block section C3 the track relay TR3 is reenergized and closes its front contact 6I. A circuit is thus completed from the positive terminal of rectifier W2, wire t2, back contact 58 of relay FR3, wire 63, front contact 6| of relay TR3, relay DR3 and wire 42 to the negative terminal of rectifier W2.

The relay DR3 is thus energized and closes its front contact 64, thereby completing an energizing circuit for the relay FR3 from Wire 55, front contact 56 of relay DR2, wires 51 and 65, front contact 64 of relay DR3, wires 85 and 61, relay FR3 to wire 42 and common wire 38. The relay FR3 is thus energized and effects the energization of the repeater relay RFR3 through a circuit including front contact 58 of relay FR3 and wire 68' and the circuit of the primary winding of the4 feed transformer T3 is thus broken at the front contact 59 of the relay RFR3 thereby cutting off the supply of signaling current to the track rails of block section C3.

The energization of the relay FR3 temporarily interrupts the circuit of the relay DR3 until the track relay when deenergized closes its back contact 6I but the energizing circuit of the relay FR3 is maintained through the front contact 69 of the relay FR3.

It will thus be seen that theA feed relay FR3 is energized and assumes its non-feed position as soon as the train has passed completely out of the corresponding block section C3v assuming that a following train is not present in the block sections Cl or C2.

A similar action occurs as the train passes through each of the block sections as will be readily understood.

As indicated in the figure the detector relays DR2 DR3 etc. and the signal control relays SR2,

SR?, etc. are of the slow-acting type so as to en-v sure suitable delay in operation. This delay in the operation of the DR relay prevents an undesired release of this relay during the short time interval when, either upon the approach of a train or upon its exit from the section, there occurs a change from one agreement circuit to the other, for energizing this relay. The slow release characteristic of the SR relays prevents undesired signal flashes shoulda DR relay fail to bridge the open circuit interval mentioned above.

Referring now to the modified system illustrated in Figure 6 the entrance of a train or vehicle into a block section is arranged to effect '5 the supply of signaling current to one block section ahead only and not to two block sections ahead as in Fig. 5, this supply being maintained until the train or vehicle has passed out of the section.

In the case of a train entering the block section C2 for instance the detector relay DB2 is deenergized as in the system of Figure 5 owing to the feed relay FR2 and the track relay TR2 of this section being both deenergized and therefore in disagreement. The energizing circuit of relay FR3 previously completed from wire 28 through wire 55, relay contact 5S, wire 5l, relay Contact 69, wire 6l, relay FR3 to wire 42 is thus broken at the relay contact 56 and the relay FR3 is deenergized. The relay FR3 is thus in its feed position and the circuit of the repeater feed relay RFR3 is interrupted at the relay contact 58 of relay FR3. The relay RFR3 is consequently deenergized and closes its back Contact, thereby effecting the supply of signaling current to the track rails of block section C3 through the transformer T3.

Assuming that the block section C3 is unoccupied the track relay TR3 is energized and the detector relay DRS is consequently maintained energized by way of back contact 58, wire 63 and front contact 6 I.

A stop signal indication is given at the signal S2 to a following train entering the block section Cl as already described in connection with the system of Figure 5 and when the train leaves block section C2 and enters block section C3 the relay DRS is deenergized and deenergizes the repeater relay RDR3. Since the relay DR2 is energized due to the exit of the train from section C2 a caution signal indication at the signal S2 will be given to a following train while when the train leaves the block section C3 and enters the block section C4, the relay DRS is again energized so that a proceed signal indication at the signal S2 is given to a following train in the block section Cl.

In both the systems of Figures 5 and 6 it will be understood that at a terminus the supply of signaling current to the first block section (not shown) of the system is effected by means of a pedal switch or its equivalent which opens the holding circuit for the feed relay FR of such rst block section in the manner previously eX- plained in connection with Fig. 3.

Although in the systems of Figures 2, 3, 4, 5 and 6 a detector relay is shown as provided for detecting agreement or disagreement between the track and feed relays of a block section it will be understood that other equivalent arrangements for this purpose may be utilized, as for instance by providing a switch device which is mechanically coupled with the movable armatures of the track and feed relays .so as to make or break a circuit in accordance with the relative positions of these armatures.

The invention is evidently not limited to the particular systems and circuit connections above described and illustrated which may be varied in many respects without exceeding the scope of the invention as defined in the appended claims.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

.75 1. In a railway signaling system the combination with track circuits constituted by the track rails subdivided into block sections, of means for at times supplying signaling current to the track rails of a block section, a relay connected across said track rails and responsive to said signaling current, and means controlled jointly by said supply means and by said relay for detecting the presence of a train in said block section.

2. In a railway signaling system the combination with track circuits constituted by the track rails subdivided into block sections, of a feed relay for at times supplying signaling current to the track rails of a block section, a track relay for said section responsive to said signaling current and having an energized and a deenergized position, and means dependent upon the position of said track relay and said feed relay for detecting the presence of a train in said section.

3. In a railway signaling system the combination with track circuits constituted by the track rails subdivided into block sections, of means operated by a train approaching a block section for supplying signaling current to the track rails of said block section, a track relay for said section having an energized and a deenergized position, and means dependent upon the position of said relay and upon said supply means for detecting the presence of a train in said section.

4. In a railway signaling system the combination with track circuits constituted by the track rails subdivided into block sections, of means for controlling the supply of signaling current to the track rails of a block section, said means having a feed position in which current is caused to be supplied to said track rails and a non-feed position in which the supply of current is cut oi, a track relay for said block section responsive to said signaling current and having an energized and a deenergized position, and means dependent upon the position of said control means and of said relay for detecting the presence of a train in said section.

5. In a railway signaling system the combination with track circuits constituted by the track rails subdivided into block sections, of means for controlling the supply of signaling current to the track rails of a block section, said means having a feed position in which current is caused to be supplied to said track rails and a non-feed position in which the supply of current is cut off, a track relay for said block section responsive to said signaling current and having an energized and a deenergized position, and means dependent upon agreement between the position of said control means and of said relay for detecting the presence of a train in said section. g

6. In a railway signaling system the combination with track circuits constituted by the track rails subdivided into block sections, of a source of signaling current, a relay operated by a train approaching a block section for controlling the supply of said current to the track rails of the block section, a track relay for said block section responsive to said signaling current, and means dependent upon both of said relays for detecting the presence of a train in said section.

'7. In a railway signaling system the combination with track circuits constituted by the track rails subdivided into block sections, of a source of signaling current, a relay operated by a train approaching a block section for controlling the supply of said current to the track rails of the block section, a track relay for said block section responsive to said signaling current, and means dependent upon correspondence 'between the noy sitions of said relays for detecting the presence of a train in said section.

8. In a railway signaling system the combination with track circuits constituted by the track rails subdivided into block sections, of a source of signaling current, a relay for controlling the supply of said current to the track rails of a block section, a track relay for said block section, each of said relays having an energized and a deenergized position, a signal for said section, and means dependent upon correspondence between the positions of said relays for controlling the operation of said signal.

9. In a railway signaling system the combination with track circuits constituted by the track rails subdivided into block sections, of means dependent upon the presence of a train in a block section for controlling the supply of signaling current to a block section in advance, a track relay for said advance block section, a signal for said advance block section, and means dependent upon said track relay and upon said control means for controlling the operation of said signal.

10. In a railway signaling systemthe combination with track circuits constituted by the track rails subdivided into block sections, of means section for controlling vthe supply of signaling current to a block section in advance, a trackl relay for said advance block sectiona signal for said advance block section, and means dependent upon trafc conditions in each of said block sections and upon the supply of signaling current to said sections for controlling the operation of said signal.

l1. In a railway signaling system the combination with track circuits constituted by the track rails subdivided into block sections, of means for effecting the supply of signaling current to the track rails of a block section by the action of a train entering the preceding block section, means for cutting off said supply by the action of the train leaving said block section, a track relay for said block section, a signal for said block section, and means controlled jointly by said supply means and by said relay for controlling the operation of said signal.

12. In a railway signaling system the combination withl track circuits constituted by the track rails subdivided into block sections, of a feed relay for controlling the supply of signaling current to each of said block sections and having a feed position and a non-feed position, a track relay for each of said sections having an energized and a deenergized position, a signal for each of said block sections, and means controlled in accordance with the corresponding positions of the feed and track relays of each of a plurality of sections ahead for controlling the operation of the signal of a block section preceding said plurality of block sections.

13. In a, railway signaling system the combination with track circuits constituted by the track rails subdivided into block sections, of a feed relay for controlling the supply of signaling current to each of said block sections and having a feed position and a non-feed position, a track relay for each of said block sections having an energized position and a deenergized position, means dependent upon the entrance of a train into a block section for causing the feed relays of a plurality of block sections ahead to assume their feed positions, and means dependent upon the corresponding positions of the feed and track relays in each of said plurality of block sections for controlling the operation of the signal of a block section preceding said plurality of blocksections.

14. In a railway signaling system the combination with track circuits constituted by the track rails subdivided into block sections, of a signal for each of said block sections, a feed relay for each of said block sections having a feed position and a non-feed position, a track relay connected across the track rails of each of said block sections and having an energized and a deenergized position, a detectorvrelay for each block section controlled by said feed relay and said track relay jointly and means controlled by said detector relay for controlling the operation of said signal.

l5. In a railway signaling system the combination with track circuits constituted by the track rails subdivided into block sections, of a signal for each of said block sections, a feed relay for each of said sections having a feed position and a non-feed position, a track relay connected across the track rails of each of said block sections and having an energized and a deenergized position, a detector relay for each block section controlled by said feed relay and said track relay jointly, and means including a detector relay for a given block section for controlling the operation of the signal of said given section and of theV signals of a plurality of block sections preceding said given section.

GEORGES CAILLE.

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